Okay forget months, forget hours, just SECONDS! mA = per second, mAh = per second.
300 mA/hour means it can provide 300 mA (per second) for an hour!
6 mA/hour over a month as a quantity.
ma/Month would be 730 times smaller than ma/hourly if total coulomb usage remains the same, because there are more seconds in a month. So. We have to make 6 smaller by 730, to get the correct ma/month value.
So lets convert 6mAh/month to hourly drain.
6 mAh / 730 = 0.0082 mA/month DRAIN.
Our usage is 0.016 mA. Which is 0.016/0.0082 = 1.95x larger than the drain.
0.025 - 0.016 = 0.009. I would argue the difference is almost the same as the discharge!
0.0082 mA vs 0.009 mA
So Ye you were spot on!
I'm done finally. This was harder than I anticipated.